GH Preparations Research Articles

Long-Acting Growth Hormone Preparations - Current Status and Future Considerations.

Long-acting GH (LAGH) preparations are currently being developed in an attempt to improve adherence. The profile of GH action following administration of LAGH raises practical questions about clinical monitoring and long-term safety and efficacy of these new therapeutic agents. Recent literature and meeting proceedings regarding LAGH preparations are reviewed. Multiple LAGH preparations are currently at various stages of development, allowing for decreased GH injection frequency from daily to weekly, biweekly, or monthly. Following administration of LAGH, the serum peak and trough GH and IGF-I levels vary depending upon the mechanism used to prolong GH action. Randomized, controlled clinical trials of some LAGH preparations have reported non-inferiority compared with daily recombinant human GH (rhGH) for improved growth velocity and body composition in children and adults with GH deficiency (GHD), respectively. No significant LAGH-related adverse events have been reported during short-term therapy. Multiple LAGH preparations are proceeding through clinical development with some showing promising evidence of short-term clinical efficacy and safety in children and adults with GHD. The relationship of transient elevations of GH and IGF-I following administration of LAGH to efficacy and safety remain to be elucidated. For LAGH to replace daily rhGH in the treatment of individuals with GHD, a number of practical questions need to be addressed including methods of dose adjustment, timing of monitoring of IGF-I, safety, efficacy, and cost-effectiveness. Long-term surveillance of efficacy and safety of LAGH preparations will be needed to answer these clinically relevant questions.

Evaluation of proteases and protease inhibitors in Heterodera glycines cysts obtained from laboratory and field populations

Proteases and protease inhibitors were evaluated in preparations ofHeterodera glycinescysts (nHglCE) obtained from glasshouse cultures (GH) and a field (LR) population. Using a FRET-peptide library comprising 512 peptide substrate pools that detect four endoprotease types (aspartic, cysteine, metallo- and serine), we found that the relative distributions of six endoproteases within the four catalytic types were similar among GH and LR preparations. However, levels of mean protease activity ( s−1(μg nHglCE)−1) across all 512 pools varied nearly eight-fold among the preparations. This variation was not related to cyst source. These qualitative (type distribution) and quantitative relationships persisted when analysis was restricted to the top 40% (activity) pools. Analysis of the top 4% of activity pools revealed some substrate cleavage site preferences between the GH and LR proteases. GH and LR preparations also differed significantly in digestion rates of trypsin and matrix metalloprotease (MMP) substrates, with LR rates two-fold greater than GH rates for each protease. By contrast, inhibition of trypsin activity inMeloidogyne incognitaextracts by heat-denatured preparations (hHglCE) was 1.6-fold greater with GH hHglCE than with LR hHglCE. Inhibition of MMP activity was the same (>60%) for each hHglCE. Fractionation of GH and LR hHglCE preparations by RP-HPLC (CH3CN/0.1% TFA system) yielded protease inhibition profiles that were similar for GH and LR. MMP inhibitors eluted at 35-40% CH3CN, and trypsin inhibitors eluted at both 5% and 35-40% CH3CN, suggesting the possibility of peptide as well as other small molecular weight inhibitors. These discoveries illustrate the importance of examiningH. glycinescysts as a source of materials for novel nematode controls.

Incidence of diabetes mellitus and neoplasia in Japanese short-statured children treated with growth hormone in the Genetics and Neuroendocrinology of Short Stature International Study (GeNeSIS).

.The primary goal of the Genetics and Neuroendocrinology of Short Stature International Study (GeNeSIS) was to assess the safety and effectiveness of Humatrope®, a GH preparation, in the treatment of pediatric patients with short stature. We report our findings in the GH-treated Japanese pediatric population focusing on the incidence of type 2 diabetes (T2D) and occurrence of neoplasms. A total of 2,345 Japanese patients were assessed for safety. During a mean observation period of 3.2 yr, T2D occurred in 3 patients (0.13%) and slowly progressive insulin-dependent diabetes mellitus (SPIDDM) related to underlying mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) in 1 patient (0.04%). Neoplasms were reported in 13 patients (0.56%), including 1 patient with brain tumor (germinoma) and 5 with craniopharyngiomas (4 recurrences); the remainder were benign, typically dermatological, neoplasms. The incidence of diabetes mellitus determined in the study did not differ from previous reports in GH-treated pediatric patients, and there was no apparent increase in the risk of new neoplastic lesions or malignant tumors.

Treatment of pituitary dwarfism in children and teenagers in the Stavropol territory

The article is devoted to the analysis of clinical and anthropometric indicators of 38 children and adolescents with pituitary dwarfism in the Stavropol region, receiving replacement therapy with recombinant growth hormone (rGH). The authors demonstrated a high growth stimulating efficacy of the rGR, as well as a positive impact on the level of blood cholesterol in children with somatotropic deficiency. Prognostic factors influencing the effectiveness of treatment were found (chronological age of initiation of therapy, baseline SDS of growth). In particular, it is shown that therapy with preparations of GH in children aged 8 to 10 years allows you to achieve a higher growth-stimulating effect in comparison with patients whose treatment is carried out at a later age. The study of the relationship between the initial deviation of the length of the body and the results of therapy in patients with growth hormone deficiency illustrates that a pronounced lag in growth is a predictive factor provides a more significant effect drugs rGR.

Long-Acting Growth Hormone: An Update.

After the introduction of recombinant human growth hormone (rhGH) in 1985, a myriad of children and adults have benefited from its growth-promoting and metabolic effects. Nowadays, current therapeutic regimens rely on daily subcutaneous GH injections that could be burdensome and inconvenient to pediatric patients. As expected with any long-term parenteral pharmacological treatment, these daily regimens may promote nonadherence, poor compliance, treatment abandonment and/or suboptimal clinical outcomes. In order to improve patient and caregiver acceptance of proposed regimens, simplified dosing schedules could potentially aid in reducing poor compliance and maximize the therapeutic end results. Long-acting GH formulations have been designed and perfected over the last two decades, and currently there are several formulations in advanced stages of research as a reasonable attempt to improve patient's adherence to GH treatment. A long-acting GH preparation allowing for reduced injection frequency is likely to improve treatment adherence and to decrease the distress and inconvenience associated with daily injections. This review presents an update about the status of current and recent efforts that have enabled the formulation of sustained-release, long-acting rhGH as it has been longed for many years in the pediatric endocrinology field.

60 YEARS OF NEUROENDOCRINOLOGY: The hypothalamo-GH axis: the past 60 years.

At the time of the publication of Geoffrey Harris's monograph on 'Neural control of the pituitary gland' 60 years ago, the pituitary was recognised to produce a growth factor, and extracts administered to children with hypopituitarism could accelerate growth. Since then our understanding of the neuroendocrinology of the GH axis has included identification of the key central components of the GH axis: GH-releasing hormone and somatostatin (SST) in the 1970s and 1980s and ghrelin in the 1990s. Characterisation of the physiological control of the axis was significantly advanced by frequent blood sampling studies in the 1980s and 1990s; the pulsatile pattern of GH secretion and the factors that influenced the frequency and amplitude of the pulses have been defined. Over the same time, spontaneously occurring and targeted mutations in the GH axis in rodents combined with the recognition of genetic causes of familial hypopituitarism demonstrated the key factors controlling pituitary development. As the understanding of the control of GH secretion advanced, developments of treatments for GH axis disorders have evolved. Administration of pituitary-derived human GH was followed by the introduction of recombinant human GH in the 1980s, and, more recently, by long-acting GH preparations. For GH excess disorders, dopamine agonists were used first followed by SST analogues, and in 2005 the GH receptor blocker pegvisomant was introduced. This review will cover the evolution of these discoveries and build a picture of our current understanding of the hypothalamo-GH axis.

The forgotten lactogenic activity of growth hormone: important implications for rodent studies.

Studies of the effects of GH and the mechanisms of its actions frequently use rats or mice and various recombinant human GH preparations. Authors of many of these studies appear unaware of the fact that, in rodents, human GH signals through both GH and prolactin (PRL) receptors; thus, treatment with human GH is equivalent to a combined treatment with GH and PRL. GH receptors and PRL receptors are present in multiple cell types. Importantly, PRL exerts major effects on brain neuroendocrine action, female and male reproduction, metabolism, body composition, immune responses, and a host of other functions; thus, treatment of rodents with recombinant human GH could affect these important physiological parameters.

12-Month effects of once-weekly sustained-release growth hormone treatment in adults with GH deficiency

The weekly sustained-release recombinant human GH formulation LB03002, showed beneficial effects in GH-deficient (GHD) adults in a previous 26-week double-blind study. Prior studies of long-acting GH preparations in adults have only been conducted for 6 or 8 months, so the effects of longer-term use are unknown; this is important to address, as replacement is given for many years in GHD adults. This open-label, 26-week study extension evaluated longer-term safety and efficacy of LB03002 over 52 weeks in adults with GHD who had previously been randomized to GH, and provides additional safety and efficacy data over 26 weeks in the cohort who had previously been randomized to placebo. Of 147 adults with GHD who completed a preceding study, 136 patients continued in this open-label study to receive LB03002 over an additional 26 weeks. This represented a continuation of long-acting GH for 26 weeks in the cohort who took this medication in the prior study (LB03002 Throughout group), and describes the first use of long-acting GH in the cohort that was randomized to placebo in the prior study (Switched to LB03002 group). The LB03002 dose was adjusted according to serum insulin-like growth factor-I (IGF-I) levels. LB03002 treatment demonstrated mean significant decreases from baseline in fat mass (FM) for both 26 (Switched group, P = 0.001) and 52 weeks (Throughout group, P = 0.002) of 1.11 (1.95) kg and 1.06 (3.16) kg, respectively. Prolonged GH treatment was effective in sustaining the increase in lean body mass (LBM), serum IGF-I and IGFBP-3 levels achieved during the first 26 weeks. Long-term treatment with the sustained-release weekly GH preparation over both 26 and 52 weeks in adults with GHD demonstrated a sustained reduction of FM with a favorable safety profile. This study extends prior knowledge about long-acting GH because it reports the most prolonged treatment of adults with any long-acting GH preparation, thereby confirming the value and safety of such agents for long-term GH replacement.

Nadir growth hormone after oral glucose overload in obese subjects

The nadir growth hormone (n-GH) in the oral glucose tolerance test (OGTT) is the gold standard for the demonstration of secretory autonomy of this hormone and a laboratory parameter necessary for the diagnosis of acromegaly (1,2). Although measurement of GH after oral glucose overload is not recommended during treatment with somatostatin analogs or GH receptor antagonists (3), normalization of n-GH continues to be necessary for the definition of “control” after surgical treatment of acromegaly (3). Nadir GH levels vary according to the assay used (4-7) and are influenced by gender, age and body mass index [BMI (4-6,8)]. The inverse correlation with BMI observed in normal subjects (4,6,8) and acromegalic patients (9) indicates the need for adjusting the n-GH cut-off as a function of BMI (4,6,8). We have previously defined n-GH reference values in subjects with a BMI ≤ 27 kg/m2 (5). The possibility that the current reference values are inadequate (overestimated) for obese subjects led to the elaboration of the present study, for which the objective was to evaluate the n-GH in the OGTT in subjects with a BMI ≥ 30 kg/m2. A total of 200 volunteers (120 women and 80 men) ranging in age from 18 to 70 years (median of 44 years), matched with 200 subjects from the previous study (5), who had a BMI ≥ 30 kg/m2 (median of 34.8 kg/m2) were studied. The selection criteria, protocol and statistical analysis are described in detail in the previous study (5). Briefly, apparently healthy subjects (excluding pregnant women) without associated diseases who were not using medications that might interfere with GH levels and who presented no abnormalities upon minimum laboratory assessment (glycemia, blood count, albumin, creatinine, TSH, GOT, GPT and bilirubin) were selected. The study was approved by the Ethics Committee of Santa Casa de Belo Horizonte. The GH Immulite kit (Diagnostic Products Corporation, Los Angeles, CA) was used for the measurement of GH since it is the kit most widely used in Brazil. In addition, the kit meets the requirements of calibrated standards against > 95% pure preparations of GH 22 kDa (10), its specificity for the 22 and 20 kDa isoforms is known (4), and its intraand interassay sensitivity and variability have been previously established (5,11). The cut-off was defined as the 97.5th percentile of the values found. The Spearman correlation test was used to analyze the correlation between n-GH and age, BMI. The nonparametric Kruskal-Wallis test and the parametric Shapiro-Wilk test were used to compare GH values obtained between groups. P values 35 years (n = 80), with higher values in the former (n-GH cut-off: 0.42 μg/L versus 0.3 μg/L, p < 0.05). There was an inverse correlation between n-GH levels and 1 Programa de Pos-graduacao, Santa Casa de Belo Horizonte, MG, Brazil 2 Faculdade de Medicina do Vale do Aco, Ipatinga, MG, Brazil

Novas opções e preparações na terapia com hormônio de crescimento

In the last twenty years, recombinant human Growth hormone (hrGH) has been available for the treatment of Growth Hormone Deficiency (GHD) in children and more recently in adults. However, the necessity of daily injections compromises the patient's compliance. Attempts to improve this compliance includes the use of pens and needle free devices, once the infusion pumps, not always physiologic, are of restricted use. When growth is the purpose of treatment, daily subcutaneous hrGH is still the most indicated. Nevertheless the expansion of GH replacement to new uses and especially in adults will need new preparations. Nowadays, the oral secretagogues have not proved efficacy to be used in clinical practice and the slow- release preparations of GH and GH releasing hormone that could improve the patient's compliance will need to be studied considering long term efficacy and safety.

Tratamento da deficiência do hormônio de crescimento (GH) em crianças: comparação entre o uso de canetas versus frascos/seringas para a aplicação do GH

The aim of this study was to compare two preparations of recombinant human GH (rGH) in the treatment of GH deficient patients. Ten prepubertal GH-deficient children were followed during 6 months. They received injections with syringe for 3 months, followed by pen administration for the subsequent 3 months. Acceptability was evaluated through a questionnaire. Waste of medication was calculated by the difference between the number of used bottles or refills and the calculated amount for the period. Treatment response was evaluated by SDS gain of height measured each 3 months. After 6 months, 90% of patients/family members declared they preferred the pen regarding technical facility and local pain, and all patients considered the pen easier to transport and store. The waste of medication was lower with pen administration, as was the final cost. We concluded that pen-administered rGH treatment is more convenient, better accepted by the patients, and leads to less waste of medication when compared to the syringe administration.

A new sustained‐release preparation of human growth hormone and its pharmacokinetic, pharmacodynamic and safety profile

Adult GH replacement is currently given by daily subcutaneous (sc) injections. Recently, sustained-release (SR) preparations of GH have been developed, the preparations being characterized by a dominant early release, resulting in supraphysiological early GH peaks, and a rapid decline thereafter. We present data on a new SR GH preparation. Phase I/II study of hGH-Biosphere(R) (SkyePharma AB, Malmo, Sweden), a new SR preparation of recombinant human GH in amylopectin microspheres coated with polylactide-coglycolide. Eight adults with severe, untreated GH deficiency (stimulated GH peaks between < 1 and 1.7 microg/l), aged 36.1 years (range 22-49 years) in good general health. Pharmacokinetic (PK), pharmacodynamic (PD) and safety data over a period of 28 days. The systemic and local tolerability of the drug was satisfactory, and no serious adverse events occurred. PK analysis showed a smaller early serum hGH peak followed by a broad sustained second peak of hGH (C(max) 1.20 microg/l at 7.2 days), and hGH levels were maintained above baseline for at least 14 days. The mean GH level never exceeded 1.1 microg/l, making the GH fluctuations comparable to continuous sc infusion. Resultant IGF-I concentrations were characterized by sustained elevation at a level near C(max) of 103 microg/l (at t(max) of 9.7 days), equal to an SD score of +0.8. IGF-I generation per administered GH was more efficient compared with reports of other SR preparations. hGH-Biosphere(R) is a well-tolerated SR GH preparation with superior efficacy in achieving target IGF-I levels without causing supraphysiological GH concentrations. Our data suggest the suitability of this preparation for longer-term trials in adults with injection frequencies of no more than once every 2-3 weeks.

Simultaneous Isolation of Prolactin and Growth Hormone from “Discarded Acid Pellet” Obtained from Buffalo Pituitaries

An acid pellet, obtained as a side fraction from a conventional gonadotropin purification pathway, has been found to contain the bulk of the pituitary lactogenic hormones (growth hormone or GH and prolactin or PRL). This discarded side fraction has been utilized to obtain buffalo lactogenic hormones (buGH and buPRL), simultaneously, and in bulk. The immunoreactivities of the purified semi‐pure buffalo GH and PRL (APECS and APP‐I, respectively) preparations were compared by direct binding ELISA with semi‐pure standard buGH and PRL (ECS and EP‐I, respectively) and were found to be as pure as standard semi‐pure buGH and buPRL. When checked by direct binding ELISA using buGH and buPRL antisera, it was observed that APECS and APP‐I were not cross‐immunoreactive. SDS‐PAGE and western blot analysis of APECS and APP‐I showed major bands located at the same positions as in the case of standard semi‐pure preparations (20 kDa for APECS and 23 kDa for APP‐I). The semi‐purified buGH and buPRL (APECS and APP‐I) were converted to a highly purified preparation by chromatographing them via Sephacryl S‐200 gel‐filtration chromatography.

Insulin-like growth factor mRNA in Barramundi (Lates calcarifer): alternative splicing and nonresponsiveness to growth hormone.

Barramundi (Lates calcarifer) is a teleost of the superorder Acanthopterygii. Barramundi IGF-I cDNA was cloned and the distribution of alternative transcripts in various barramundi tissues was investigated using rt-PCR and RPA. It was demonstrated that in barramundi tissues, IGF-I mRNAs were represented by two transcripts corresponding to the reported salmonid Ea-2 and Ea-4. The acute effect of GH on hepatic IGF-I mRNA levels was investigated. Seven hours after intraperitonal administration of either 6 micrograms of recombinant bream GH/g body weight or saline, no significant increase in the levels of either of the two transcripts could be observed. The presence of GH receptors in the barramundi liver was demonstrated in binding assays using recombinant bream GH and liver membrane preparations. An analysis of a barramundi IGF-I genomic sequence encompassing the three exons that encode the E domain suggested that the pattern of splice site utilization is determined by the degree of homology of the splicing signals to the consensus splice site sequences.

Immunostimulating effect of growth hormone: in-vivo administration of growth hormone in rainbow trout enhances resistance to Vibrio anguillarum infection.

In-vivo administration of purified (nGH) and recombinant (rGH) chum salmon, Oncorhynchus keta, growth hormone enhanced the survival of rainbow trout, O. mykiss, against virulent Vibrio anguillarum. Macrophages obtained from rainbow trout that were treated in vivo with either GH preparation showed enhanced stimulation of the chemiluminescent responses induced by opsonized V. anguillarum cells and increased phagocytic activities. However, the serum bactericidal activity against V. anguillarum was not enhanced in fish injected with nGH or rGH. These findings show that in-vivo administration of either GH preparation can effectively prime macrophages and increase the resistance to V. anguillarum in rainbow trout.

Different paradigms for elicitng sodium appetite in rats have differential effects on gustatory neural responses in the nucleus of the solitary tract

This chapter lists and discusses miscellaneous hormones and prostaglandins. Miscellaneous harmones such as calcitonin, parathyroid hormones (PTH) analogs, somatotrophin (human growth hormone; hGH) and its side effects have been discussed. It explains prior contamination and notes that the two most frightening complications of GH therapy are the contamination of prions in pituitary GH preparations and the possible association of leukemia and GH therapy. It explores the relationship of leukemia to GH therapy. It lists thyroid effects as one of the plausible side effects of GH therapy. The side effects of corticotrophin-releasing hormone (CRH), and growth-hormone-releasing hormone (GHRH) have been discussed. protirelin (thyrotrophin-releasing hormone; TRH), somatostatin and analogs, gonadorelin (gonadotrophin-releasing hormone; GnRH), gonadorelin (gonadotrophin-releasing hormone; GnRH) and analogs, vasopressin and analogs, and oxytoein have been discussed. It also discusses the side effects of prostaglandins (pg) in cardiovascular diseases, prostaglandins in gastrointestinal disease, clinical use of prostacyclin (PGI2) and analogs, prostaglandins in urology, prostaglandins in obstetrics, and prostaglandins in ophthalmology have been discussed in the chapter.

Lactogenic actions of different growth hormone preparations in pregnant and lactating rats

We studied the capacity of different GH preparations, natural human (h)GH, recombinant hGH (rhGH), rat (r)GH, ovine (o)GH, bovine (b)GH and porcine (p)GH, and ovine prolactin (oPRL), to stimulate lactogenesis in ovario-hysterectomized pregnant rats or intact lactating rats treated with bromocriptine (BC). Ovariohysterectomy (OVX-HYS) performed at 0800 h on day 19 of pregnancy induced lactogenesis, i.e. increases in mammary casein and lactose and positive response to the oxytocin test, 28 h later. Lactogenesis was prevented by treatment with BC (1.5 mg/kg) immediately after surgery (OVX-HYS-BC). The hormones were given at doses of 0.25 or 0.5 mg/rat (except rhGH given only at 0.5 mg/rat) at 1200 and 2000 h on day 19. Casein was increased by both doses of oPRL and hGH, rhGH and 0.25 mg oGH, and lactose by both doses of oPRL, rhGH and 0.25 mg rGH. The other GH preparations had no effect. The oxytocin test demonstrated the presence of milk in the mammary tissues of the OVX-HYS rats and in the OVX-HYS-BC plus oPRL (0.25 and 0.5 mg) or rhGH-treated groups. Injection of BC to pregnant rats at 2000 h on day 20 and at 0800 h on day 21 decreased litter growth on the first 4 days postpartum. Two-thirds of the litters resumed growth after day 4, indicating the recuperation of milk production, while the rest never recuperated. Serum prolactin in BC-treated rats was reduced until day 4 postpartum. On day 6 the rats which had recuperated had normal values, while those which had still not recuperated had lower values. BC-treated rats were injected s.c. with 0.25 mg each of oPRL, hGH, rGH, oGH, bGH or pGH, or 0.25 or 0.5 mg rhGH/rat, immediately postpartum and 12, 24 and 36 h later. hGH and 0.5 mg rhGH induced levels of milk production similar to controls except on day 3. oPRL and rhGH (0.25 mg), induced a partial reversion of the effect of BC. rGH and oGH had a slight effect on days 1 and 2 and all the litters resumed growth on day 7. In contrast, pGH and bGH were inactive. The affinity of hGH for the prolactin receptor, measured as displacement of 125I-labelled oPRL binding to crude liver membranes, was comparable with that of oPRL. While rhGH was ten times less active than oPRL, rPRL was 100 times lower and all the other GH preparations had at least 10(4) times lower capacity to displace 125I-labelled oPRL.(ABSTRACT TRUNCATED AT 400 WORDS)

Growth hormone secretion in the horse: unusual pattern at birth and pulsatile secretion through to maturity.

A heterologous radioimmunoassay was developed and validated for the measurement of horse GH in plasma. It utilized recombinant-derived bovine GH as the radiolabelled ligand, a guinea-pig anti-porcine GH serum as first antibody and pituitary-derived horse GH as standard. Cross-reactivities were high with all of the pituitary and recombinant-derived GH preparations tested (49-140%) and very low (< 0.3%) with horse FSH, LH and prolactin. A synthetic analogue of GH-releasing factor(1-29) stimulated the expected pattern of GH release in foals. Plasma GH concentrations in foals were low at birth (< 20 ng/ml) but rose sharply to a definite and, in most cases, very large peak (18-195 ng/ml) during the first 30-40 min post partum, followed by a steady decline to basal levels again by 60-100 min post partum. GH secretion was clearly pulsatile in all older foals tested (2 weeks, 1 month and 4 months of age) and in six adults (three mares and three stallions), all bled at 15-min intervals for 7-8 h. Basal levels and pulse amplitudes were higher in foals than in adults and pulse frequency was higher in stallions than in mares (3-5 pulses/8 h vs 1-2 pulses/8 h). Pulsatile secretion was further characterized in one mare by simultaneous sampling of jugular vein and pituitary cavernous sinus blood. Peak GH concentrations in cavernous sinus blood draining the pituitary gland were more than tenfold higher than the corresponding peak concentrations in peripheral circulation.(ABSTRACT TRUNCATED AT 250 WORDS)

A 12-kilodalton N-glycosylated growth hormone-related peptide is present in human pituitary extracts.

This study was designed to investigate whether N-linked glycosylation could account for the presence of glycosylated GH forms (G-GH) in human pituitary extracts. The study was carried out in commercially available pituitary GH preparations (pitGH). Recombinant GHs obtained from eu- or prokaryotic cells were used as controls. Radioiodinated GHs were incubated in tubes containing Concanavalin-A (Con-A) attached to a Sepharose 4B matrix. Pituitary G-GH forms were selectively displaced from Con-A by adding N-acetyl-D-glucosamine or methyl-alpha-D-mannopyranoside and electrophoresed. Autoradiographies of these gels identified a 12-kilodalton (12K) band as the glycosylated form. Due to the fact that this peptide was partially immunoprecipitated with an anti-GH serum and the absence of detectable PRL in the pitGH extracts, it would indicate that such a glycopeptide was GH related. Endoglycosidase-F treatment of pitGH extracts induced a decrease in the mol wt of that 12K peptide, as indicated by the changes observed in its mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This demonstrated that the sugar moieties were N-linked. When recombinant GHs were assayed by a similar method, no specific binding to Con-A was detected. NH2-terminal amino acid sequence analysis from the 12K band demonstrated that this band was composed by three peptides. Peptide 1 corresponds to the GH-N 102-119 sequence. Interestingly, peptide 2 exhibits GH-V 1-18 sequence, while peptide 3 seems to be a novel GH-related peptide. Taken together, these data suggest that the pituitary G-GH form found in human pituitary extracts is derived not from the "normal" GH-N gene, but, rather, from the GH-V gene or another unidentified gene. The potentially important pathophysiological implications of this finding need to be investigated.

COMPARATIVE STUDY OF GROWTH HORMONE (GH) IHMUNOGENICITY IN NORMAL VARIANT SHORT CHILDREN

The immunogenicity of 3 recombinant GH preparations used to treat 117 children have been compared. Children were 4-12 years of age, 70 M, 47 F. Height <2 SD for age and gender, height velocity <4.5 cm/year and bone age delay > 2 SD for age. Fifteen children were with chronic renal failure, and 102 with growth failure without known etiology. GH response to provocative tests in all children were > 10 mcg/L. The children were treated with Bio-Tropin (Bio-Technology General, Israel;n=55, 6 years), Norditropin (Novo-Nordisk, Denmark; n=62, 3-4 yrs) and Saizen (serono; n=8, 0.9-1 year). For the detection of anti GH antibodies (ab), a double antibody immunoassay was utilized. Thirty of the samples were analyzed by two different laboratories. Non of the patients developed anti GH ab. It is concluded that in contrast to the past experience where the detection of anti GH ab in children treated with different brands of authentic GH was frequent, the degree of purity of contemporary preparations prevents development of anti GH ab.